Soil series profile

Washington soil series

Washington is a well drained soil with a silt loam surface, mapped on 90,370 acres in 13 counties across 2 states. Hydrologic group B.

#3816 by mapped area fine-loamy Ultic Hapludalfs (Alfisols)

Drainage class: Well drained
Hydrologic group: B
Typical topsoil pH: 6.5
Mapped area: 90k

Typical Washington profile

Texture and pH by depth

Depth to scale. More strongly shaded layers hold more clay. Horizon names are the soil survey's (A = topsoil, B = subsoil, C = parent material).

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Typical Washington horizons (representative values)
Depth	Texture	pH	Clay	Sand	Organic matter
0–7 in (Ap)	Silt loam	6.5	23%	22%	3%
7–16 in (Bt1)	Clay loam	6.5	30%	36%	0.25%
16–50 in (Bt2)	Clay loam	6.5	30%	36%	0.25%
50–60 in (BC)	Gravelly loam	6.5	23%	40%	0.25%

Representative values from the most extensive Washington map unit (Washington silt loam, 3 to 8 percent slopes, survey area NJ041). Other map units of this series vary within the series range.

Stock photo for illustration, not a sample of this soil series. Credit on the Sources & method page.

What this means

What Washington soil means for gardens, lawns and septic systems

For gardens

Typical topsoil in Washington soils is slightly acidic: pH 6.5, the range most vegetables, flowers and lawn grasses prefer.

Loamy topsoil (loam, silt loam and similar) covers 100% of mapped Washington acres: generally the easiest soil to garden, holding moisture without staying waterlogged. The most common surface texture is silt loam (95% of mapped Washington acres).

100% of mapped Washington acres is moderately well to excessively drained, which suits most garden plants.

For lawns and yards

Most land is in hydrologic groups B and C, where rain soaks in at a moderate pace.

For a septic system

For conventional septic absorption fields, NRCS rates 93% of the acres in mapped Washington soils very limited, 7% somewhat limited and 0% not limited.

Where the soil is very limited (slow permeability, a high water table, flooding, shallow bedrock or steep slopes), alternative systems such as mound or sand-filter designs are common and cost more.

Only a licensed site evaluation or perc test at the actual lot decides whether a system is allowed and which design.

Generated from the mapped numbers above using fixed rules, not a site visit. See how these notes are written.

Where Washington soil is found

Mapped acres

Washington is mapped in Pennsylvania and New Jersey.

Counties with the most mapped Washington soil
County	Acres	Share of county land
Warren County, NJ	24,448	10.8%
Lehigh County, PA	23,305	10.6%
Northampton County, PA	21,300	9.0%
Lycoming County, PA	5,122	0.7%
Union County, PA	4,870	2.4%
Hunterdon County, NJ	2,480	0.9%
Snyder County, PA	2,283	1.1%
Northumberland County, PA	2,266	0.8%
Columbia County, PA	1,654	0.5%
Morris County, NJ	1,356	0.5%
Bucks County, PA	793	0.2%
Montour County, PA	486	0.6%
Somerset County, NJ	6	0.0%

Septic absorption fields

NRCS rating, share of Washington acres

Not limited 0%

Somewhat limited 7%

Very limited 93%

Septic tank absorption field rating across mapped Washington acres. Scale 0 to 100% of mapped land.

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Septic tank absorption field rating across mapped Washington acres.
Category	Share of acres
Not limited	0.0%
Somewhat limited	7.3%
Very limited	92.7%

Drainage, water table and flooding

Share of Washington acres

Depth to seasonal high water table: About 2.2 feet (26 in) (median where reported).
Flooding: Not mapped as flooding on most acres.
Slope: Typically 2–12% (median 6%).
Topsoil organic matter: Median 3%.

Drainage class

Excessively drained 0%

Somewhat excessively drained 0%

Well drained 96%

Moderately well drained 4%

Somewhat poorly drained 0%

Poorly drained 0%

Very poorly drained 0%

Drainage class across mapped Washington acres. Scale 0 to 100% of mapped land.

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Drainage class across mapped Washington acres.
Category	Share of acres
Excessively drained	0.0%
Somewhat excessively drained	0.0%
Well drained	96.3%
Moderately well drained	3.7%
Somewhat poorly drained	0.0%
Poorly drained	0.0%
Very poorly drained	0.0%

Hydrologic soil group

A: fast infiltration (mostly sandy or gravelly) 0%

B: moderate infiltration 96%

C: slow infiltration 4%

D: very slow infiltration (clayey, shallow or wet) 0%

A/D: D as is, A if drained 0%

B/D: D as is, B if drained 0%

C/D: D as is, C if drained 0%

Hydrologic soil group across mapped Washington acres. Scale 0 to 100% of mapped land.

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Hydrologic soil group across mapped Washington acres.
Category	Share of acres
A: fast infiltration (mostly sandy or gravelly)	0.0%
B: moderate infiltration	96.3%
C: slow infiltration	3.7%
D: very slow infiltration (clayey, shallow or wet)	0.0%
A/D: D as is, A if drained	0.0%
B/D: D as is, B if drained	0.0%
C/D: D as is, C if drained	0.0%

Sources & data dates

Source: USDA NRCS Soil Survey Geographic Database (SSURGO), queried through Soil Data Access. Public domain.
Data date: SSURGO as published on November 3, 2026 (most recent survey area update October 26, 2026). NRCS refreshes SSURGO each October.
Scope: All map unit components named Washington (component kind "Series") in SSURGO: 90,370 acres.
Method: Shares are by mapped acres of Washington components. The profile comes from the single largest Washington component. Full methodology.

Independent reference site. No government affiliation or endorsement.

Full narrative description: USDA Official Soil Series Description for Washington.